[media] v4l: vsp1: Add header display list support

Display lists can operate in header or headerless mode. The headerless
mode is only available on WPF0, to be used with the display engine. All
other WPF instances can only use display lists in header mode.

Implement support for header mode to prepare for display list usage on
WPFs other than 0.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>